1. Field of the Invention
The present invention relates generally to signal processors and more particularly to digital signal processors.
2. Description of the Related Art
A growing list of communication devices (e.g., pagers, cellular telephones, laptop computers, point-to-point radios and automotive radios) presently compete for access to wireless communication networks. Unfortunately, a variety of modulation processes have been adopted worldwide as wireless communication standards.
In the United States, for example, the Telecommunication Industry Association has adopted an Interim Standard (IS-95) which specifies the modulation processes of binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK), the Post Office Standard Advisory Group has adopted (for pagers) the modulation process of frequency shift keying (FSK) and the United States Digital Cellular System (USDC) has adopted an Interim Standard (IS-54) which specifies the modulation process of .pi./4 quadrature phase shift keying (.pi./4QPSK). Other communication standards (e.g., ERMES in Europe and PDC in Japan) add still other modulation processes such as M-ary frequency shift keying (M-FSK) and differential quadrature phase shift keying (DQPSK).
Present communication transceivers are typically configured to be compatible with only a selected one of these various modulation processes. Accordingly, communication device users are either limited in their access to different wireless communication services or must accept the additional cost of obtaining a plurality of transceivers.
Although a transceiver that is compatible with a variety of modulation processes could be realized with a "brute force" integration of existing transceiver structures, this approach generally results in penalties of larger size, greater cost, duplication of functions and operability limitations.